Specific CD8 T-cell Responses Research Articles

Essential role for Batf3-dependent dendritic cells in regulating CD8 T-cell response during SARS-CoV-2 infection.

SARS-CoV-2 infection elicits robust CD8 T-cell responses, yet the identity of the mechanisms playing dominant roles in initiating the virus-specific CD8 T-cell responses are largely unknown. In the present study, we interrogate the contribution of the cDC1 subset to SARS-CoV-2-specific CD8 T-cell immunity. For this purpose, we used a novel murine line which combines the SARS-CoV-2 susceptible K18-hACE2 transgenic and the Batf3 deficient mice which lack the cDC1 subset. We demonstrate that in the absence of cDC1, viral-specific CD8 T-cell responses were severely impaired both in the draining lymph node as well as in the lungs, during the effector phase of SARS-CoV-2 infection. Furthermore, SARS-CoV-2 specific memory CD8 T-cells in the lungs and spleens were also significantly impacted, whereas humoral responses, as well as CD4 T-cells were not affected. Additionally, we demonstrate that the absence of cDC1 subset, and the consequent impaired CD8 T-cell responses, resulted in significant increase in SARS-CoV-2 viral load in the lungs. The conclusions of the study were further independently corroborated in an additional COVID-19 murine model consisting infection with a mouse-adapted SARS-CoV-2 virus. These results underscore a specific role for Batf3-dependent DC in regulating SARS-CoV-2 specific CD8 T-cell responses and may contribute to future vaccine design and immunization strategies.

Infliximab aggregates produced in severe and mild elevated temperature stress conditions induce an extended specific CD4 T-cell response

Aggregation has been widely described as a factor contributing to therapeutic antibody immunogenicity. Although production of high-affinity anti-drug antibodies depends on the activation of CD4 T lymphocytes, little is known about the T-cell response induced by antibody aggregates, especially for aggregates produced in mild conditions resulting from minor handling errors of vials. Large insoluble infliximab (IFX) aggregates produced in severe elevated temperature stress conditions have been previously shown to induce human monocyte-derived dendritic cell (moDC) maturation. We here showed that large IFX aggregates recruit in vitro a significantly higher number of CD4 T-cells compared to native IFX. Moreover, a larger array of T-cell epitopes encompassing the entire variable regions was evidenced compared to the native antibody. We then compared the responses of moDCs to different types of aggregates generated by submitting IFX to mild conditions of various times of incubation at an elevated temperature. Decreasing stress duration reduced aggregate size and quantity, and subsequently altered moDC activation. Of importance, IFX aggregates generated in mild conditions and not altering moDC phenotype generated an in vitro T-cell response with a higher frequency of CD4 T cells compared to native IFX. Moreover, cross-reactivity studies of aggregate-specific T cells showed that some T cells could recognize both native and aggregated IFX, while others responded only to IFX aggregates. Taken together, our results suggest that aggregation of antibodies in mild elevated temperature stress conditions is sufficient to alter moDC phenotype in a dose-dependent manner and to increase T-cell response.

KS01.6.A UCPVAX-GLIO: A PHASE II TRIAL EVALUATING THE IMMUNOGENICITY AND EFFICACY OF AN ANTI-TELOMERASE VACCINE IN PATIENTS WITH NEWLY DIAGNOSED GBM

Abstract BACKGROUND The Telomerase Reverse Transcriptase (TERT) is activated in 85%-90% of cancers, and glioblastomas (GBM) harbor the highest incidence of activating mutations within its promoter (over 85% of patients). This high expression of TERT in cancers and its role in oncogenesis make TERT a very promising tumor antigen for immunotherapy, especially in GBM. UCPvax is a therapeutic vaccine in which two CD4 helper peptides derived from TERT are mixed with the Montanide adjuvant. This phase IIa trial was designed to test the immunogenicity, safety and efficacy of UCPvax in patients with newly diagnosed GBM. PATIENTS AND METHODS In this first cohort of the UCPvax-glio trial (NCT04280848), patients with unmethylated MGMT non-mutated IDH1 GBM were included if they had a Karnofsky Performance status (KPS) ≥ 70%, a steroid treatment < 10mg/ day equivalent prednisone, and lymphocytes count ≥ 0.8 x 109/L. One month after completion of radiation/ temozolomide (TMZ), patients started UCPvax vaccinations on days 1, 8, 15, 29, 36 and 43, then every two months until tumor progression. Patients did not receive any additional cure of TMZ because of the unmethylated MGMT promoter status. Peripheral blood mononuclear cells were collected before treatment, at 1 and 2 months after treatment, and at each vaccination boost. The primary endpoint was the anti-TERT specific CD4 T-cell response at 2 months using IFN-gamma ELISPOT. Secondary endpoints included safety, progression-free survival (PFS) and overall survival (OS). RESULTS All the 31 patients (median age 60-yr old, median KPS 90%) included in this study received at least one vaccination. Vaccinations were given for 4.5 months on average (min 2- max 14). At baseline, only one patient had a pre-existing anti-TERT CD4 T-cell response (3%). After immunizations, de novo induction and/or amplification of an anti-TERT response were found in 29/30 patients (97%). An epitope spread response against other tumor-associated antigens was detected in 12/25 patients (48%). All patients developed local skin reactions (≤ grade 2), 16 patients complained of transient asthenia (≤grade 2), and 13 patients experienced local pain (≤grade 2). No severe (grade 3-4) toxicity was attributable to the vaccination. In the intent-to-treat population (n = 31), the PFS was 8.9 months (95% CI: 7.6-10.6) and the median OS was 17.9 months (95% CI: 16-23). Two years after diagnosis, 26% of the patients were still alive. OS was significantly improved in the patients developing an epitope spread response vs the others (20.8 versus 14.1 months, respectively, p = 0.03). CONCLUSION s: In this population of unmethylated MGMT GBM patients, UCPVax is highly immunogenic and provides an interesting OS rate. These data strongly support the completion of the second ongoing cohort, assessing UCPvax in combination with TMZ for GBM patients with methylated MGMT promoter status.

Neutralizing antibody and T-cell responses against SARS-CoV-2 variants by heterologous CoronaVac/ChAdOx-1 vaccination in elderly subjects with chronic obstructive pulmonary disease

BackgroundData on humoral and cellular immune responses against SARS-CoV-2 after receiving heterologous CoronaVac/ChAdOx-1 (CoVac/ChAd) vaccination in subjects with chronic obstructive pulmonary disease (COPD) are still limited. Therefore, we determined the neutralizing antibody (NAb) and T-cell responses against SARS-CoV-2 wild type (WT) and variants of concern (VOCs) in COPD patients. MethodsThe levels of NAb as well as specific CD4 and CD8 T-cell responses against SARS-CoV-2 WT and VOCs were determined in COPD patients before and after vaccination. ResultsFour weeks after vaccinations, the median levels of % inhibition of NAb against SARS-CoV-2 WT, Alpha, Beta, and Delta variants were significantly higher compared to pre-vaccination. The induction of NAb against Omicron was very low compared to other variants. At four weeks after vaccination, in comparison to pre-vaccination, the increasing trend of TNF-α-, IFN-γ-, IL-4-, IL-17-, IL-10-, and FasL-producing CD4 T-cells upon stimulation with WT spike peptides were demonstrated. No difference in T-cell responses to spike peptides of Alpha, Beta, and Delta variants and their WT homologs was observed. ConclusionHeterologous CoVac/ChAd vaccine induced the production of NAb against SARS-CoV-2 WT, Alpha, Beta, and Delta variants, but low for Omicron in COPD patients. Induction of CD4 T-cell subset responses was slightly observed by this vaccine regimen.Clinical Trials Registry: This study was approved by the Clinical Trials Registry (Study ID: TCTR20210822002).

Anti-telomerase vaccine in patients with newly diagnosed, unmethylated MGMT glioblastoma: A phase II study.

2005 Background: TERT, a subunit of the telomerase complex, is largely expressed in almost all cancers. Among those cancers, glioblastomas (GBM) harbor the highest incidence of activating mutations within the TERT promoter (over 85% of patients). This high incidence underlies the potential role of TERT in oncogenesis, and points out TERT as a highly relevant tumor target in GBM. UCPvax is a therapeutic vaccine composed of two CD4 helper peptides derived from TERT, combined with the montanide adjuvant. We conducted a phase IIa trial to test the immunogenicity, safety and efficacy of UCPvax in patients with newly diagnosed GBM. Methods: Key inclusion criteria were: histologically confirmed, non-mutated IDH1 glioblastoma, unmethylated MGMT promoter status, previous treatment with concomitant radiotherapy and temozolomide (TMZ), Karnofsky Performance status (KPS) ≥ 70%, steroids < 10mg/ day equivalent prednisone, and lymphocytes count ≥ 0.8 x 109/L. One month after completion of radiation/TMZ, patients started UCPvax vaccinations on days 1, 8, 15, 29, 36 and 43, then every two months until tumor progression, without additional cure of TMZ. Peripheral blood mononuclear cells were collected before treatment, at 1 and 2 months after treatment and, at each vaccination boost. The primary endpoint was an anti-TERT specific CD4 T-cell response measured ex vivo in peripheral blood using IFN-gamma ELISPOT at 2 months. Secondary endpoints included safety, overall survival (OS) and progression-free survival (PFS). Results: Thirty-one adult patients (median age 60-yr old, median KPS 90%) were included in this study. All patients received at least one vaccination, and vaccinations were given for 4.5 months on average (min 2– max 14). At baseline, only one patient had a pre-existing anti-TERT CD4 T-cell response (3%). After immunizations, de novo induction and/or amplification of an anti-TERT response were found in 29/30 pts (97%). An epitope spread response against other tumor-associated antigens was detected in 12/25 pts (48%). No severe (grade 3–4) toxicity was attributable to the vaccination. All patients developed local skin reactions (≤ grade 2), 16 patients complained of transient asthenia (≤grade 2), and 13 patients experienced local pain (≤grade 2). In the intent-to-treat population (n=31), the PFS was 8.9 months (95% CI: 7.6–10.6) and the median OS was 17.9 months (95% CI: 16–23). Two years after diagnosis, 26 % of the patients were still alive. OS was significantly improved in the patients developing an epitope spread response vs the others (19.3 vs 15.8 months, respectively, p=0.03). Conclusions: UCPVax is highly immunogenic and provides an interesting OS rate in this population of poor prognosis, unmethylated MGMT GBM patients. These data support further clinical studies of UCPvax in GBM patients. Clinical trial information: NCT04280848 .

MT-6402, an engineered toxin body (ETB) targeting PD-L1: Interim efficacy and safety data.

2552 Background: MT-6402, an engineered toxin body (ETB) , has been designed to be effective in patients (pts) previously treated with checkpoint inhibitors (CPIs) by utilizing 3 unique mechanisms of action (MOA): (i) remodeling of the tumor microenvironment by elimination of PD-L1+ immunosuppressive cells like myeloid-derived suppressor cells (MDSCs), (ii) direct cell kill of PD-L1+ expressing tumor cells, (iii) delivery of HLA-A*02 restricted cytomegalovirus (CMV) peptide pp65 to PD-L1 expressing cells to direct a CMV specific CD8 T-cell response against the tumor. Methods: Dose escalation continues with MT-6402 (QW in 4-week cycles) in pts with relapsed/refractory PD-L1+ solid tumors. After clearing doses of 16, 24, 32, 42 and 63 µg/kg, 83 µg/kg is being evaluated. Safety, tolerability, efficacy, pharmacokinetics, and pharmacodynamic data are reported. Results: MT-6402 at 63 µg/kg in 1 pt with metastatic nasopharyngeal carcinoma (NPC) who progressed after radiation, chemotherapy, and CPI (PD-L1 CPS=2%, not HLA-A*02) resulted in a PR (63% reduction in target lesion) after 2 cycles. This pt had an increase in CD8/CD4 and immune activation cytokines (IL-2, TNFα, IFNγ) consistent with elimination of MDSCs. A pt with NSCLC (osseous disease only) that had progressed after CPI showed resolution of 3/4 osseous metastases and decreased radiotracer uptake by the remaining bone metastasis. This patient had high PD-L1 tumor expression and HLA-A*02/CMV+. Complete CMV-specific T-cell extravasation was noted by C1D8 consistent with haplotype-specific CMV antigen delivery for presentation on the tumor surface by MHC class I. All cohorts had reductions in peripheral PD-L1+ MDSCs, monocytes and dendritic cells after MT-6402 without effect on PD-L1- cells with the most depletion at the highest doses. Most pts displayed CD8+ T-cell expansion and elevations of serum IL-2 and TNFα, consistent with PD-L1-mediated immunotolerance. MT-6402 was well tolerated with 2 dose limiting toxicities reported: Grade (G)2 maculopapular rash at 24 µg/kg, G3 IRR at 63µg/kg. No G ≥ 4 AEs occurred. Infusion-Related Reactions in 3 pts (G1, G2, and G3) and Cytokine Release Syndrome (G1 [2 pts] at both 32 and 42µg/kg and G2 [1 pt] at 16µg/kg) occurred. Conclusions: MT-6402 utilizes three PD-L1-targeted and unique MOAs: direct cell-kill, reduced immunosuppression, and increased immunorecognition. As of Feb 2023, 5 dose cohorts have completed. MT-6402 was well tolerated without CLS or payload-derived toxicity as is observed with traditional immunotoxins and ADCs, respectively. A PR in 1 pt with CPI-refractory NPC (CPS 2%, CMV-) and regression of osseous metastases in a pt with NSCLC (TPS 80%, HLA-A*02/CMV+) following disease progression on CPI occurred. These results show MT-6402 monotherapy activity though unique MOAs and provide rationale for MT-6402 dose expansion. Clinical trial information: NCT04795713 .

Neutralizing Antibody and T-Cell Responses against SARS-CoV-2 Wild-Type and Variants of Concern in Chronic Obstructive Pulmonary Disease Subjects after ChAdOx-1/ChAdOx-1 Homologous Vaccination: A Preliminary Study.

Data on immunogenicity of adenovirus-vectored vaccine in chronic obstructive pulmonary disease (COPD) patients is limited. Therefore, we aimed to determine the humoral and cellular immune responses after homologous ChAdOx-1 vaccination in subjects with COPD. COPD subjects and age- and sex-matched healthy elderly receiving ChAdOx-1 homologous vaccination were included. The levels of neutralizing antibodies (NAb) and specific CD4 and CD8 T-cell responses against SARS-CoV-2 wild-type (WT) and variants of concern (VOCs: Alpha, Beta, Delta, and Omicron) were measured. Eight COPD patients were matched with eight control participants. After vaccination for 4 and 12 weeks, % inhibition of NAb against Alpha, Beta, and Delta in both groups were comparable and significantly higher than baseline. The percentage inhibition of NAb at the 12th week was significantly dropped from the 4th week in each group. The NAb against the Omicron variant, however, were much lower than Alpha, Beta, Delta variants. The increasing trend in the number of CD4 T-cells producing TNF-α, IFN-γ, IL-10, and FasL upon stimulation with spike peptides of WT and VOCs was observed in COPD patients compared to the healthy group. These responses were not observed in CD8 T-cells. Homologous ChAdOx-1 vaccination could induce comparable NAb against the SARS-CoV-2 WT, Alpha, Beta, Delta, and Omicron variants between COPD and healthy elderly. The CD4 T-cell responses did not differ between COPD patients and healthy control.

Phenotypic Profile of Mycobacterium tuberculosis-Specific CD4 T-Cell Responses in People With Advanced Human Immunodeficiency Virus Who Develop Tuberculosis-Associated Immune Reconstitution Inflammatory Syndrome.

Tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) is a frequent complication of cotreatment for TB and human immunodeficiency virus (HIV)-1. We characterized Mycobacterium tuberculosis (Mtb)-specific CD4 T-cell phenotype and transcription factor profile associated with the development of TB-IRIS. We examined the role of CD4 T-cell transcription factors in a murine model of mycobacterial IRIS. In humans, we used a longitudinal study design to compare the magnitude of antiretroviral therapy, activation, transcription factor profile, and cytotoxic potential of Mtb-specific CD4 T cells between TB-IRIS (n = 25) and appropriate non-IRIS control patients (n = 18) using flow cytometry. In the murine model, CD4 T-cell expression of Eomesodermin (Eomes), but not Tbet, was associated with experimentally induced IRIS. In patients, TB-IRIS onset was associated with the expansion of Mtb-specific IFNγ+CD4 T cells (P = .039). Patients with TB-IRIS had higher HLA-DR expression (P = .016), but no differences in the expression of T-bet or Eomes were observed. At TB-IRIS onset, Eomes+Tbet+Mtb-specific IFNγ+CD4+ T cells showed higher expression of granzyme B in patients with TB-IRIS (P = .026). Although the murine model of Mycobacterium avium complex-IRIS suggests that Eomes+CD4 T cells underly IRIS, TB-IRIS was not associated with Eomes expression in patients. Mycobacterium tuberculosis-specific IFNγ+CD4 T-cell responses in TB-IRIS patients are differentiated, highly activated, and potentially cytotoxic.

Reinfection with SARS-CoV-2 in solid-organ transplant recipients: Incidence density and convalescent immunity prior to reinfection.

BackgroundLong‐term protective immunity to severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) remains poorly characterized, particularly in solid organ transplant (SOT) patients.MethodWe determined the incidence density of SARS‐CoV‐2 reinfection in a cohort of adult SOT recipients initially infected between March 1st, 2020 and March 30th, 2021 and included those with initial infection before or after transplantation. Incidence density was the total cases divided by total days after initial diagnosis with active graft.ResultsOf 210 infected recipients, five (2.4%) developed reinfection, including two who had received full mRNA vaccination, but none developed hypoxia. The incidence density for reinfection was 9.4 (95% confidence interval [CI] 3.9‐22.6) and for primary infection the density was 9.1 (95% CI 7.9–10.5) cases/100,000 patient days. Two recipients had immunity evaluated in the weeks prior to reinfection, by measuring immunoglobulin‐G (IgG) antibody titer to the SARS‐CoV‐2 receptor binding domain and virus‐specific CD4+ and CD8+ T‐cell reactivity following stimulation with SARS‐CoV‐2 peptide pools. Both mounted virus specific CD4 T‐cell responses prior to reinfection (1.19% and 0.28% of total CD4 T cells) and both had reactive IgG testing (1.30 and 4.99 signal/cut off ratio).ConclusionsThis suggests that SOT recipients infected with SARS‐CoV‐2 remain at high risk for reinfection even after generating cellular and humoral immune responses.

Phase I trial of adjuvant mature autologous dendritic cell/allogeneic tumor lysate vaccines in combination with temozolomide in newly diagnosed glioblastoma.

BackgroundGlioblastoma (GBM) has poor prognosis despite aggressive treatment. Dendritic cell (DC) vaccines are promising, but widespread clinical use has not been achieved, possibly reflecting manufacturing issues of antigen choice and DC potency. We previously optimized vaccine manufacture utilizing allogeneic human GBM tumor cell lysate and potent, mature autologous DCs. Here, we report a phase I study using this optimized DC vaccine in combination with standard therapy.MethodsFollowing surgical resection and radiation with concurrent temozolomide (TMZ), newly diagnosed adult GBM patients received intradermal DC vaccines plus TMZ. Primary endpoints were safety and feasibility. Immune and treatment responses were recorded.ResultsTwenty-one patients were enrolled in this study. One progressed between leukapheresis and vaccine manufacture. Twenty patients received treatment per protocol. Vaccine doses (≥15) were generated following a single leukapheresis for each patient. No dose-limiting vaccine toxicities were encountered. One patient had symptomatic, histologically proven pseudoprogression. Median progression-free survival was 9.7 months. Median overall survival was 19 months. Overall survival was 25% at 2 years and 10% at 4 years. One patient remains progression-free 5 years after enrollment. Specific CD8 T-cell responses for the tumor-associated antigen gp100 were seen post-vaccination. Patients entered the trial with a leukocyte deficit compared to healthy donors which partly normalized over the course of therapy.ConclusionsThis vaccine platform is safe and highly feasible in combination with standard therapy for newly diagnosed patients. Imaging, histological, survival, and immunological data suggest a positive biological response to therapy that warrants further investigation.

Abstract S05-01: Profound CD8 T-cell responses towards SARS-CoV-2 OFR1ab in COVID-19 patients

Abstract While there is accumulating evidence on the antibody response against SARS-CoV-2, we are only beginning to acquire knowledge regarding the SARS-CoV-2 specific CD8 T-cell response. Therefore, it is an urgent matter to gain a deeper insight into the virus specific CD8 T-cell response to both assist vaccine design and provide tools to evaluate the vaccine-induced T-cell responses. To address this issue, we have analyzed samples from 20 COVID-19 patients for CD8 T-cell recognition of 500 predicted SARS-CoV-2-derived epitopes restricted to 10 of the most common HLA-A and HLA-B alleles. For each HLA allele, the top 50 epitopes were selected based on predicted binding affinity and likelihood of successful proteasomal processing. In addition, SARS-CoV-2 epitope predictions shared by the science community were considered. To probe for CD8 T-cell recognition of the selected epitopes, we made use of our in-house technology based on multiplexing of peptide HLA (pHLA) multimers conjugated to fluorescent dyes. Our data demonstrated that CD8 T-cell reactivity against SARS-CoV-2 was common. Remarkably, a substantial fraction of the observed CD8 T-cell responses were directed towards the ORF1ab polyprotein 1ab. These CD8 T-cell responses were frequently of a profound magnitude. In particular, a CD8 T-cell response towards a potentially immunodominant epitope (TTDPSFLGRY) restricted to the HLA-A*01:01 allele was found in all patients positive for this allele. Interestingly, the fraction of SARS-CoV-2 specific CD8 T cells expressing the inhibitory receptor NKG2A was higher as compared to bulk CD8 T cells. In conclusion, the fact that a major part of the identified SARS-CoV-2 specific CD8 T-cell response is directed against a part of the viral genome that is not included in the majority of vaccine candidates currently in development may potentially influence their clinical activity and toxicity profile. Citation Format: Anastasia Gangaev, Steven L. Ketelaars, Sanne Patiwael, Anna Dopler, Olga I. Isaeva, Kelly Hoefakker, Sara De Biasi, Cristina Mussini, Giovanni Guaraldi, Massimo Girardis, Cami M.P. Talavera Ormeno, Paul J.M. Hekking, Neubury M. Lardy, Mireille Toebes, Robert Balderas, Ton N. Schumacher, Huib Ovaa, Andrea Cossarizza, Pia Kvistborg. Profound CD8 T-cell responses towards SARS-CoV-2 OFR1ab in COVID-19 patients [abstract]. In: Proceedings of the AACR Virtual Meeting: COVID-19 and Cancer; 2020 Jul 20-22. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(18_Suppl):Abstract nr S05-01.

QuantiFERON-TB Gold Plus combined with HBHA-Induced IFN-γ release assay improves the accuracy of identifying tuberculosis disease status

ObjectiveQFT-Plus's newly added antigen elicited a specific CD8 T-cell response, which is closely related to active TB (ATB), and the IGRA based on Heparin-binding haemagglutinin (HBHA-IGRA) is a promising tool in latent tuberculosis infection (LTBI) diagnosis. The objective of our study is to evaluate whether the combination of QFT-Plus and HBHA-IGRA can improve the diagnosis accuracy of ATB and LTBI. Methods135 healthcare workers (HCWs) and 57 patients with active pulmonary TB in a Chinese TB Hospital were recruited, HCWs underwent screening for LTBI using the QFT-Plus assay. Flow cytometry was used to analyze the distribution of peripheral blood T lymphocyte subsets in active TB patients with positive culture result. Then, the patients with ATB, individuals with LTBI and healthy TB-uninfected controls (HC) were tested by QFT-Plus and HBHA-IGRA respectively, and the efficiency of distinguishing LTBI from ATB by QFT-Plus and HBHA-IGRA were evaluated by Receiver Operating Characteristic (ROC) curves. ResultsQFT-Plus TB2-TB1 which was positively correlated with CD8 T-cell response (r = 0.731, P < 0.001) in peripheral blood was significantly higher in ATB than LTBI and HC (median 0.47 IU/mL versus 0.02 IU/mL and 0.00 IU/mL, respectively; both P < 0.0001). While the HBHA-induced IFN-γ response did not differ between ATB and HC (median 12.12 pg/mL versus 10.95 pg/mL; P = 0.463), but was significantly higher in the LTBI (median 69.67 pg/mL; both P < 0.0001). The ROC area under the curve (AUC) for identifying ATB and LTBI was 0.769 (95% CI: 0.652–0.886; P = 0.0001) for QFT-Plus TB2-TB1, and 0.886 (95% CI:0.791–0.982; P＜0.0001) for HBHA-IGRA. After combining the HBHA-IGRA with QFT-Plus results, the accuracy of identifying ATB and LTBI was improved to 85.7% from 74.3%. ConclusionsHBHA-based IGRA better differentiates between LTBI and ATB compared to QFT-Plus CD8 T-cell response. In addition, combining HBHA-IGRA and QFT-Plus improves the accuracy of identifying tuberculosis disease status.

Preserved specific anti-viral T-cell response but associated with decreased lupus activity in SLE patients with cytomegalovirus infection

SLE is an autoimmune disease characterized by aberrant autoantibody production and immune dysfunctions. Whether the anti-CMV immunity is impaired in SLE patients is poorly understood. We investigated the specific anti-viral T-cell response in SLE patients with CMV infection and its possible impacts on clinical manifestations in lupus. CD28 null T-cell percentages were measured by flow cytometry in 89 SLE patients and 58 healthy controls. A specific anti-CMV CD8 T-cell response was assessed ex vivo by the production of intracellular cytokines in response to CMV phosphoprotein 65 (pp65) by flow cytometry. Clinical manifestations and immune parameters were analysed in SLE patients according to their CMV serostatus. CD28 null T cells were significantly expanded in SLE patients. When the anti-CMV pp65 CD8 polyfunctional T cell response was analysed, as defined by production of at least three of four functional cytokines or effectors (intracellular IFN-γ, IL-2, TNF-α and surface CD107a), the results demonstrated that it was not impaired in SLE patients. In contrast, when comparing clinical manifestations, there were lower anti-ds-DNA levels and decreased SLEDAI in SLE patients with CMV infection. Furthermore, the expansion of CD4+CD28 null T cells was negatively associated with anti-ds-DNA levels and SLEDAI in these lupus patients. In SLE patients with CMV infection, the specific anti-CMV CD8 T-cell response is preserved but is associated with decreased disease activity and lower anti-DNA levels among these patients, suggesting CMV infection may mitigate lupus activity.

A First-in-Human Phase I Study of INVAC-1, an Optimized Human Telomerase DNA Vaccine in Patients with Advanced Solid Tumors.

Human telomerase reverse transcriptase (hTERT) is highly expressed in >85% of human tumors and is thus considered as a good tumor-associated antigen candidate for vaccine development. We conducted a phase I study to investigate the safety, tolerability, clinical response, and immunogenicity of INVAC-1, a DNA plasmid encoding a modified hTERT protein in patients with relapsed or refractory solid tumors. INVAC-1 was either administered by intradermal route followed by electroporation or by Tropis, a needle-free injection system. Safety and tolerability were monitored by clinical and laboratory assessments. Progression-free survival and overall survival were reported using Kaplan-Meier survival analysis. Immunogenicity was studied by ELISpot, Luminex, and Flow Cytometry. Twenty-six patients were treated with INVAC-1 administered at three dose levels (100, 400, and 800 μg). Vaccination was well tolerated and no dose-limiting toxicity was reported. One treatment-related grade 3 SAE was reported. Fifty-eight percent of patients experienced disease stabilization. PFS was 2.7 months, median OS was 15 months, and 1-year survival was reached for 65% of patients. INVAC-1 vaccination stimulated specific anti-hTERT CD4 T-cell response as well as cytotoxic CD8 T-cell response. No evidence of peripheral vaccine-induced immunosuppression was observed. INVAC-1 vaccination was safe, well tolerated, and immunogenic when administered intradermally at the three tested doses in patients with relapsed or refractory cancers. Disease stabilization was observed for the majority of patients (58%) during the treatment period and beyond.See related commentary by Slingluff Jr, p. 529.

Characterization of specific CD4 and CD8 T-cell responses in QuantiFERON TB Gold-Plus TB1 and TB2 tubes

The new generation of the IGRA QuantiFERON-TB Gold Plus (QFT-Plus) includes two antigen tubes, TB1 and TB2 which contain specific Mycobacterium tuberculosis peptides designed to stimulate both CD4 and CD8 T-cells. TB1 is designed to target cell mediated responses from CD4 T-cells, while TB2 contains newly designed peptides designed to also stimulate CD8 T-cells. We identified specific CD4 and CD8 T-cell clones that recognize different regions spanning the length of the CFP-10 protein in M. tuberculosisto directly test in QFT-Plus TB1 and TB2 tubes, followed by Interferon-gamma detection by the QFT-Plus ELISA. These clones showed specific responses to the different QFT-Plus tubes, the CD4 T-cell clone showed dose-dependent responses to both TB1 and TB2 tubes, while the CD8 T-cell clones showed specific and targeted responses to the QFT-Plus TB2 tube (>140-fold difference) versus the QFT-Plus TB1 tubes using the QFT-Plus ELISA. This testing provides direct evidence of the specificity of CD8 T-cell mediated response in QFT-Plus TB2 tubes.

Cancer Stem Cell Vaccination With PD-L1 and CTLA-4 Blockades Enhances the Eradication of Melanoma Stem Cells in a Mouse Tumor Model.

Immune checkpoint inhibitors and monoclonal antibodies reinvigorate cancer immunotherapy. However, these immunotherapies only benefit a subset of patients. We previously reported that ALDH tumor cells were highly enriched for cancer stem cells (CSCs), and ALDH CSC lysate-pulsed dendritic cell (CSC-DC) vaccine was shown to induce CSC-specific cytotoxic T lymphocytes. In this study, we investigated the CSC targeting effect of the CSC-DC vaccine combined with a dual blockade of programmed death-ligand 1 and cytotoxic T-lymphocyte-associated protein (CTLA-4) in B16-F10 murine melanoma tumor model. Our data showed that animals treated with the dual blockade of programmed death-ligand 1 and CTLA-4 and CSC-DC vaccine conferred significantly more tumor regression than the CSC-DC vaccine alone. Importantly, the triple combination treatment dramatically eliminated ALDH CSCs in vivo. We observed that CSC-DC vaccine in combination with anti-PD-L1 and anti-CTLA-4 administration resulted in ∼1.7-fold fewer PD-1CD8 T cells and ∼2.5-fold fewer CTLA-4CD8 T cells than the populations observed following the CSC-DC vaccination alone. Moreover, significant antitumor effects and dramatically eliminated ALDH CSCs following the triple combination treatment were accompanied by significantly enhanced T-cell expansion, suppressed transforming growth factor β secretion, enhanced IFN-γ secretion, and significantly enhanced host specific CD8 T-cell response against CSCs. Collectively, these data showed that administration of a-PD-L1 and a-CTLA-4 combined with CSC-DC vaccine may represent an effective immunotherapeutic strategy for cancer patients in clinical.

Highlighting Advances in the Treatment of Gliomas

Highlighting Advances in the Treatment of Gliomas

A new vaccination strategy to trigger specific CD4 T-cell response in chronic viral infection

A new vaccination strategy to trigger specific CD4 T-cell response in chronic viral infection

Graft-versus-leukemia effect with a WT1-specific T-cell response induced by azacitidine and donor lymphocyte infusions after allogeneic hematopoietic stem cell transplantation

BackgroundAzacitidine (Aza) and donor lymphocyte infusion (DLI) therapy has recently been reported as an effective salvage therapy for relapsed acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Despite the high response rate and relatively long period of remission, most patients relapse again. The immunologic mechanism of the response and limited efficacy remain unknown. Case ReportAza + DLI therapy was performed for a patient with therapy-related MDS (t-MDS), who had relapsed after allogeneic peripheral blood stem cell transplantation. We observed a powerful graft-versus-leukemia (GVL) effect accompanied by an evident Wilms tumor antigen 1 (WT1)-specific CD8 T-cell response. Remission continued for 15 months, but finally the patient relapsed. The kinetics of the WT1-specific CD8 T cells were inversely associated with WT1 messenger RNA (mRNA), suggesting a WT1-driven GVL effect. DiscussionA difference of T-cell phenotype between the whole T cells and the WT1-specific CD8 T cells was observed. It is of note that the memory phenotype of the WT1-specific T cell was limited and decreased early. The immunoescape mechanism was partly supported by loss of the memory phenotype due to failure of expansion and differentiation. ConclusionOur data suggested that a WT1-specific T-cell response at least partly contributes to the GVL effect induced by Aza + DLI. A strategy for maximizing and maintaining the memory phenotype of the CTL may be required for durable remission.

First characterization of the CD4 and CD8 T-cell responses to QuantiFERON-TB Plus

QuantiFERON®-TB Gold Plus (QFT-Plus) is the new generation of QuantiFERON-TB Gold In-Tube test to identify latent tuberculosis infection (LTBI). QFT-Plus includes TB1 and TB2 tubes which contain selected Mycobacterium tuberculosis (Mtb) peptides designed to stimulate both CD4 and CD8 T-cells. Aim of this study is the flow cytometric characterization of the specific CD4 and CD8 T-cell responses to Mtb antigens contained within QFT-Plus. We enrolled 27 active tuberculosis (TB) patients and 30 LTBI individuals. Following stimulation with TB1 and TB2, antigen-specific T-cells were characterized by flow cytometry. Data were also correlated with the grade of TB severity. TB1 mainly elicited a CD4 T-cell response while TB2 induced both CD4 and CD8 responses. Moreover, the TB2-specific CD4 response was detected for both active TB and LTBI patients, whereas the TB2-specific CD8 response was primarily associated with active TB (p=0.01). To our knowledge, we report the first characterization of the CD4 and CD8 T-cell response to QFT-Plus. CD8 T-cell response is mainly due to TB2 stimulation which is largely associated to active TB. These results provide a better knowledge on the use of this assay.